The field of this invention is that of electrically conductive spring materials and members and of methods for making such spring materials and members.
Electrically conductive spring materials and members used in making electrically conductive spring contacts in switches and in sockets for mounting integrated circuits on printed circuit boards and the like are presently made from a variety of electrically conductive metal materials such as beryllium copper, phosphor bronze, cupro nickels, nickel silver and copper-clad steels including copper-clad stainless steels. The electrically conductive spring materials used in specific switch and socket applications are usually selected for meeting various performance specifications for specific applications while also achieving the desired performance at the lowest overall cost taking into account not only the basic material cost but also the costs involved in manufacturing and assembling electrically conductive spring members made from the selected materials. In that selection process, it is typically found that beryllium copper materials are required for meeting the higher performance specifications and such materials are widely used even though the basic material costs are high and even though the spring members which use such materials are difficult and expensive to form. Typically beryllium copper materials have limited formability properties making them difficult to bend into desired contact member shapes and those materials require special heat-treatments and the like after forming to provide shaped spring members with their intended spring characteristics for meeting the high performance specifications. Typically copper-clad steel spring materials have been available at relatively much lower cost but have not had performance characteristics suitable for meeting the requirements of many high performance electrically conductive spring applications.